Household appliances such as cooking ranges and laundering machines for performing housekeeping tasks such as cooking and cleaning, respectively, are traditionally equipped with a user interface that permits a user to control the appliance. The user interface is usually placed on the top or the front side of the appliance, and can comprise an information display and/or a keyboard or user operable buttons or protruding knobs.
However, the presence of such a user interface can make the household appliance difficult to clean, and it also restricts the design possibilities of the appliance.
An alternative user interface is disclosed per se in WO 02/054169. More precisely, WO 02/054169 discloses “a data input device comprising: an illuminator operative to illuminate at least one engagement plane by directing light along said at least one engagement plane; a two-dimensional imaging sensor viewing said at least one engagement plane from a location outside said at least one engagement plane for sensing light from said illuminator scattered by engagement of a data entry object, such as a user's finger, with said at least one engagement plane; a data entry processor receiving an output from said two-dimensional imaging sensor and providing a data entry input to utilization circuitry; and a data entry matrix projector operative to project at least one visually sensible data entry matrix onto a projection surface underlying said at least one engagement plane”.
However, in a household appliance for performing a housekeeping task, not only information provided by the user is of interest, but also information on the environment in which the household appliance operates.